This invention relates to printed circuit board connectors and, more particularly, to an improved multiport coaxial connector assembly system for separably interconnecting two printed circuit boards.
With the ever increasing speed of computer circuitry, new problem are encountered. The increased speed comes about from a reduction of the size of the semiconductor components, such as IC gates, and results in faster signal rise times to produce more electromagnetic radiation from signal carrying conductors. As semiconductor component size is reduced, the components become more sensitive to noise and cross talk. This interference problem has in the past been solved by surrounding the signal carrying pin connected to the printed circuit board by other pins. These other pins are connected to ground to provide a "return path" for radiated signals so as to provide shielding. This traditional shielding method is uneconomical because four to eight pins may be required per signal to provide cross talk and noise immunity, impacting upon the space available on the printed circuit board.
A connector assembly which addresses the problems of shielding and connector density is disclosed in co-pending U.S. patent application Ser. No. 07/297,636, filed Jan. 13, 1989, assigned to the assignee of the present invention. This co-pending application discloses a connector assembly for use with a printed circuit board wherein a true coaxial connection is provided. The connector assembly includes a housing block with a plurality of bores aligned with the plated-through apertures of the circuit board. Each of the bores contains a coaxial connector subassembly which provides surface contact with the signal pads and ground pads surrounding the apertures on the printed circuit board. As disclosed in the aforereferenced co-pending application, individual wire terminations may be made to th printed circuit board through the connector assembly. What s desired, in addition, is an arrangement whereby a large number of connections may be made to the printed circuit board through the connector assembly. In particular, it would be desirable to have an arrangement wherein the connector assembly disclosed in the aforereferenced co-pending application is mounted on one printed circuit board (sometimes referred to as a mother board) and another printed circuit board (sometimes referred to as a daughter board) may be mechanically and electrically connected to the one printed circuit board through the aforereferenced connector assembly.
It is therefore an object of this invention to provide a signal connector compatible with the aforedescribed connector to provide a "system" approach for connecting daughter boards to mother boards.
It is another object of this invention to provide a connector assembly wherein the signal path through the interconnection minimizes reflections to thereby minimize degradation of the signal wave form.
It is a further object of this invention to provide a connector assembly with relatively distortionless interconnection for signal waveforms with significant harmonics up to ten GHz.
It is yet another object of this invention to provide a connector assembly wherein no cross talk is induced in the connector assembly and which it is immune to electromagnetic interference, from both a radiative and susceptibility standpoint (i.e., wherein the connector is inherently shielded).
It is yet a further object of this invention to provide a connector assembly of high density interconnection, eliminating the need for adjacent pin groundings.
It is still another object of this invention to provide a connector assembly mountable to a printed circuit board without requiring soldering or exposing the board to severe thermal shock, so that the connector assembly is separable from the printed circuit board.
It is still a further object of this invention to provide a connector assembly allowing the use of isolated grounds if required by the particular application.